This invention relates to a probe unit which is to be subjected to pressure contact with electrode pads of a given electronic part such as a liquid crystal panel or the like when the electronic part is tested.
Conventional probe units used for testing a given electronic part such as a liquid crystal panel have a large number of leads arranged in an array on the surface of an insulative sheet. The distal end terminals of the respective leads are elastically contacted, under pressure, with corresponding electronic pads of the electronic part, and testing is carried out by a tester connected to the basal ends of the leads.
A rigid holder is adhered to the surface of the insulative sheet on the other side of the elongate leads, and the lead terminals are allowed to project from the terminal of the holder together with the insulative sheet terminal. The lead terminals are bent at those projecting portions together with the film terminals, so that they are pressure contacted with the corresponding pads.
Recently, in order to facilitate a very small pitch arrangement of the leads, there was employed a process for growing the leads on the insulative sheet by plating, through application of the additive process, etc. However, since the leads are irregularly grown by plating, they are not made uniform in height in the direction of their thickness. This gives rise to a problem in that the leads do not evenly contact with the corresponding electrode pads.
Moreover, in order to reduce the contact area with the insulative sheet, the lead terminals are repeatedly bent together with the sheet end edge and pressure contacted with the corresponding electrode pads. This also gives rise to a problem in that peel-off occurs between the lead tip terminals and the sheet end edge.
Since the leads are very tiny and weak, it is difficult to obtain a sufficient elastic force, i.e., pressure contact force for each lead terminal.
The present invention has been accomplished in view of the above problems.